The world premiere of Murder-on-the-Lake, among this season’s Shaw Festival offerings in Niagara-on-the-Lake, is part improv show, part send-up to the traditional drama we love, and out-of-the-box murder mystery party game that were all the rage of the ’90s. In brief, it’s an absolute hoot and quite the surprise on the traditional NOL stage. I loved it.

Billed as “a spontaneous theatre creation” written by Rebecca Northan (who also directs it and is in the cast) and Bruce Horak (another ensemble member), the audience is given a head’s up that one of them may be selected to participate playing the role of the detective. And that’s where the fun begins.

The set up is a lovely lake house with a group of friends reuniting on the anniversary of the death of a friend….yes, it was a yet-to-be-solved murder. And then…there’s yet another murder! Our audience-detective has two crimes to solve!

The ensemble – Kristopher Bowman, Cosette Derome, Sochi Fried, Virgilia Griffith, Martin Happer, Horak, Northan, and Travis Seetoo – is terrific and throw plenty of good bones to Detective to help him play along. While it’s clear there is a script, there is plenty of skillful ad libbing, including getting the audience-actor to engage. At the performance Theatre Companion and I saw, the audience-actor actually ad libbed the best line of the show!

In a send up to the grand old board game Clue, each ensemble member is attired monochromatically: think of Col. Mustard and Prof. Plum, and costumer Rose Tavormina. The heavy color saturation of their attire is a great pop of boldness against the elegant trappings of the lake house. (Great sets are always a Shaw Festival visual treat, and Judith Bowden nailed a good one here). What’s a murder mystery without a thunder storm and flickering lights? Jeff Pybus and John Gzowski on light and sound design respectively do this up right.

The most charming part of this show is the way it’s double cast (the director is the police chief and the dead woman, OK, that’s triple casting), and there are some fun theatre devices here to move that along winningly.

While not entirely your typical murder story, there’s enough of that rooted in here to keep it real and the whole construction is so clever and so fun, Miss Marple and Hercule Poirot would be in stitches.

Murder-on-the-Lake runs two hours and 30 minutes with a brief intermission to stretch your legs and exercise your little grey cells. It runs until October 4 at the Royal George Theatre. (Note, this theatre is accessible, but there are some challenges and the staff is wonderfully kind and helpful). Find details at http://www.shawfest.com.